Rewarding and Reinforcing Effects of 25H-NBOMe in Rodents

The novel psychoactive substance 25E-NBOMe induces reward-related behaviors via dopamine D1 receptor signaling in male rodents

Novel psychoactive substances (NPSs) are new psychotropic drugs designed to evade substance regulatory policies. 25E-NBOMe (2-(4-ethyl-2,5-dimethoxyphenyl)-N-(2-methoxybenzyl)ethanamine) has recently been identified as an NPS, and its recreational misuse has been reported to be rapidly increasing. However, the psychopharmacological effects and mechanisms of 25E-NBOMe have not been studied. We examined the abuse potential of 25E-NBOMe using the conditioned place preference in male mice and self-administration paradigms in male rats. Additionally, immunoblot assay, enzyme-linked immunosorbent assay, and microdialysis were used to determine the molecular effects of 25E-NBOMe in the nucleus accumbens (NAc). Our data demonstrated that 25E-NBOMe induces conditioned place preference, and the dopaminergic signaling in the NAc mediates these. Following 25E-NBOMe administration, expression of dopamine transporter and dopamine D1 receptor (D1DR) were enhanced in the NAc of male mice, and NAc dopamine levels were reduced in both male mice and rats. Induction of intracellular dopaminergic pathways, DARPP32, and phosphorylation of CREB in the NAc of male mice was also observed. Significantly, pharmacological blockade of D1DR or chemogenetic inhibition of D1DR-expressing medium spiny neurons in the NAc attenuated 25E-NBOMe-induced conditioned place preference in male mice. We also examined the hallucinogenic properties of 25E-NBOMe using the head twitch response test in male mice and found that this behavior was mediated by serotonin 2A receptor activity. Our findings demonstrate that D1DR signaling may govern the addictive potential of 25E-NBOMe. Moreover, our study provides new insights into the potential mechanisms of substance use disorder and the improvement of controlled substance management.

Abused drug-induced intracranial self-stimulation is correlated with the alteration of dopamine transporter availability in the medial prefrontal cortex and nucleus accumbens of mice

Intracranial self-stimulation (ICSS) of the medial forebrain bundle in mice is an experimental model use to assess the relative potential of reward-seeking behaviors. Here, we used the ICSS model to evaluate the abuse potential of 18 abused drugs: 3-Fluoroethamphetamine (3-FEA); methylphenidate; cocaine; dextroamphetamine; alpha-Pyrrolidinobutyrophenone (α-PBT); 4'-Fluoro-4-methylaminorex (4-FPO); methamphetamine; larocaine; phentermine; paramethoxymethamphetamine (PMMA); phendimetrazine; N-(1-adamantyl)-1-pentyl-1H-indazole-3-carboxamide (AKB-48); Naphthalen-1-yl-(4-pentyloxynaphthalen-1-yl)methanone (CB-13); 4-Ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210); Naphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-018); N-(ortho-methoxybenzyl)-4-ethylamphetamine (4-EA-NBOMe); N-[(2-Methoxyphenyl)methyl]-N-methyl-1-(4-methylphenyl)propan-2-amine (4-MMA-NBOMe); and 1-[1-(4-methoxyphenyl)cyclohexyl]piperidine (4-MeO-PCP). We determined dopamine transporter (DAT) availability in the medial prefrontal cortex (mPFC), striatum, and nucleus accumbens (NAc) after drug treatment. DAT availability in the mPFC and NAc significantly correlated with the ICSS threshold after drug treatment. Extracellular dopamine and calcium levels in PC-12 cells were measured following drug treatment. After drug treatment, Spearman rank and Pearson correlation analyses showed a significant difference between the extracellular dopamine level and the ICSS threshold. After drug treatment, Spearman rank correlation analysis showed a significant correlation between Ca2+ signaling and the ICSS threshold. A positive correlation exists between the ICSS threshold and DAT availability in the mPFC and NAc provoked by abused drugs. The relative potential of drug-induced reward-seeking behavior may be related to DAT availability-mediated extracellular dopamine levels in the mPFC and NAc.

25X-NBOMe compounds - chemistry, pharmacology and toxicology. A comprehensive review

Recently, a growing number of reports have indicated a positive effect of hallucinogenic-based therapies in different neuropsychiatric disorders. However, hallucinogens belonging to the group of new psychoactive substances (NPS) may produce high toxicity. NPS, due to their multi-receptors affinity, are extremely dangerous for the human body and mental health. An example of hallucinogens that have been lately responsible for many severe intoxications and deaths are 25X-NBOMes - N-(2-methoxybenzyl)-2,5-dimethoxy-4-substituted phenethylamines, synthetic compounds with strong hallucinogenic properties. 25X-NBOMes exhibit a high binding affinity to serotonin receptors but also to dopamine, adrenergic and histamine receptors. Apart from their influence on perception, many case reports point out systemic and neurological poisoning with these compounds. In humans, the most frequent side effects are tachycardia, anxiety, hypertension and seizures. Moreover, preclinical studies confirm that 25X-NBOMes cause developmental impairments, cytotoxicity, cardiovascular toxicity and changes in behavior of animals. Metabolism of NBOMes seems to be very complex and involves many metabolic pathways. This fact may explain the observed high toxicity. In addition, many analytical methods have been applied in order to identify these compounds and their metabolites. The presented review summarized the current knowledge about 25X-NBOMes, especially in the context of toxicity.